The osquery shell and daemon use optional command line (CLI) flags to control initialization, disable/enable features, and select plugins. These flags are powered by Google Flags and are somewhat complicated. Understanding how flags work in osquery will help with stability and greatly reduce issue debugging time.
Most flags apply to both tools,
osqueryd. The shell contains a few more to help with printing and other helpful one-off modes of operation. Expect Linux / OS X / and Windows to include platform specific flags too. Most platform specific flags will control the OS API and library integrations used by osquery. Warning, this list is still not the 'complete set' of flags. Refer to the techniques below for obtaining ground truth and check other components of this Wiki.
Flags that do not control startup settings may be included as "options" within configuration. Essentially, any flag needed to help osquery determine and discovery a configuration must be supplied via command line arguments. Google Flags enhances this to allow flags to be set within environment variables or via a "master" flag file.
To see a full list of flags for your osquery version use
--help or select from the
$ osqueryi osquery> select * from osquery_flags;
To see the flags that have been updated by your configuration, a flag file, or by the shell try:
osquery> select * from osquery_flags where default_value <> value;
Command line only flags
A special flag, part of Google Flags, can be used to read additional flags from a line-delimited file. On OS X and Linux this
--flagfile is the recommended way to add/remove the following CLI-only initialization flags.
Include line-delimited switches to be interpreted and used as CLI-flags:
--config_plugin=custom_plugin --logger_plugin=custom_plugin --distributed_plugin=custom_plugin --watchlog_level=2
--flagfile is provided, osquery will try to find and use a "default" flagfile at
/etc/osquery/osquery.flags.default. Both the shell and daemon will discover and use the defaults.
Configuration control flags
Config plugin name. The type of configuration retrieval, the default filesystem plugin reads a configuration JSON from disk.
Built-in options include: filesystem, tls
The filesystem config plugin's path to a JSON file. On OS X the default path is /var/osquery/osquery.conf. If you want to read from multiple configuration paths create a directory: /etc/osquery/osquery.conf.d/. All files within that optional directory will be read and merged in lexical order.
Check the format of an osquery config and exit. Arbitrary config plugins may be used. osquery will return a non-0 exit if the parsing failed.
Request that the configuration JSON be printed to standard out before it is updated. In this case "updated" means applied to the active config. When osquery starts it performs an initial update from the config plugin. To quickly debug the content retrieved by custom config plugins use this in tandem with
osquery daemon control flags
Force osqueryd to kill previously-running daemons. The daemon will check for an existing "pidfile". If found, and if it contains a pid of a process named "osqueryd", the process will be killed.
Path to the daemon pidfile mutex. The file is used to prevent multiple osqueryd processes starting.
Disable userland watchdog process. osqueryd uses a watchdog process to monitor the memory and CPU utilization of threads executing the query schedule. If any performance limit is violated the "worker" process will be restarted.
Performance limit level (0=loose, 1=normal, 2=restrictive, 3=debug). The default watchdog process uses a "level" to configure performance limits. The higher the level the more strict the limits become. The "debug" level disables the performance limits completely.
The watchdog "profiles" can be overridden for Memory and CPU Utilization.
If this value is non-0 the watchdog level (
--watchdog_level) for maximum memory is overridden. Use this if you would like to allow the
osqueryd process to allocate more than 100M, but somewhere less than 1G.
If this value is non-0 the watchdog level (
--watchdog_level) for maximum sustained CPU utilization is overridden. Use this if you would like to allow the
osqueryd process to use more than 90% of a thread for more than 6 seconds of wall time.
Attempt to convert all UNIX calendar times to UTC.
Windows builds include a
--uninstall that will create a Windows service using the
osqueryd.exe binary and preserve an optional
--flagfile if provided.
Backing storage control flags
If using a disk-based backing store, specify a path. osquery will keep state using a "backing store" using RocksDB by default. This state holds event information such that it may be queried later according to a schedule. It holds the results of the most recent query for each query within the schedule. This last-queried result allows query-differential logging.
Helpful for debugging database problems. This will print a line for each key in the backing store. Note: There could be MBs worth of data in the backing store.
Extensions control flags
Path to the extensions UNIX domain socket. Extensions use a UNIX domain socket for communication. It is very uncommon to change the location of the file. The osquery shell may use extensions, but the socket location is relative to the user invoking the shell and does not support concurrent shells.
Optional path to a list of autoloaded and managed extensions. If using an extension to provide a proprietary config or logger plugin the extension process can be started by the daemon. Include line-delimited paths to extension executables. See the extensions deployment page for more details on extension autoloading.
Seconds to wait for autoloaded extensions to register. osqueryd may depend on a config plugin from an extension. If the requested config plugin name is not registered within the timeout the daemon will exit with a failure.
Seconds delay between extension connectivity checks. Extensions are loaded as processes. They are expected to start a thrift service thread. The osqueryd process will continue to check this API. If an extension process is incorrectly stopped, osqueryd will detect the connectivity failure and unregister the extension.
Optional path to a list of autoloaded library module-based extensions. Modules are similar to extensions but are loaded as shared libraries. They are less flexible and should be built using the same GCC runtime and developer dependency library versions as osqueryd. See the extensions deployment page for more details on extension module autoloading.
Optional comma-delimited set of extension names to require before osqueryi or osqueryd will start. The tool will fail if the extension has not started according to the interval and timeout.
Remote settings (optional for config/logger/distributed) flags
When using non-default remote plugins such as the tls config, logger and distributed plugins, there are process-wide settings applied to every plugin.
When using tls-based config or logger plugins, a single TLS host URI is used. Using separate hosts for configuration and logging is not supported among the tls-based plugin suite. Provide a host name and optional port, e.g.:
See the tls/remote plugin documentation. Optionally provide a path to a PEM-formatted client TLS certificate.
See the tls/remote plugin documentation. Optionally provide a path to a decrypted/password-less PEM-formatted client TLS private key.
See the tls/remote plugin documentation. Optionally provide a path to a PEM-formatted server or authority certificate bundle. This path will be used as either an explicit set of accepted certificates or an OpenSSL-verify path directory of well-formed filename certificates.
See the tls/remote plugin documentation. Remote plugins use an enrollment process to enable possible server-side implemented authentication and identification/authorization. Config and logger plugins implicitly require enrollment features. It is not recommended to disable enrollment and this option may be removed in the future.
See the tls/remote plugin documentation. A very simple authentication/enrollment involves posting a deployment or staged shared secret. This secret should be protected on the host, but potentially shared among an enterprise or fleet. Provide a path for the osquery process to read and use during enrollment phases.
The tls endpoint path, e.g.: /api/v1/config when using the tls config plugin. See the other tls_ related CLI flags.
The configuration tls endpoint refresh interval. By default a configuration is fetched only at osquery load. If the configuration should be auto-updated set a "refresh" time to a value in seconds. This option enforces a minimum of 10 seconds. If the configuration endpoint cannot be reached during run, during an attempted refresh, the normal retry approach is applied.
The total number of attempts that will be made to the remote config server if a request fails.
The tls endpoint path, e.g.: /api/v1/logger when using the tls logger plugin. See the other tls_ related CLI flags.
See the tls/remote plugin documentation. An enrollment process will be used to allow server-side implemented authentication and identification/authorization. You must provide an endpoint relative to the
See the tls/remote plugin documentation. This is a number of seconds before checking for buffered logs. Results are sent to the TLS endpoint in intervals, not on demand (unless the period=0).
Optionally enable GZIP compression for request bodies when sending. This is optional, and disabled by default, as the deployment must explicitly know that the logging endpoint supports GZIP for content encoding.
It is common for TLS/HTTPS servers to enforce a maximum request body size. The default behavior in osquery is to enforce each log line be under 1M bytes. This means each result line from a query's results cannot exceed 1M, this is very unlikely. Each log attempt will try to forward up to 1024 lines. If your service is limited request bodies, configure the client to limit the log line size.
Use this only in emergency situations as size violations are dropped. It is extremely uncommon for this to occur, as the
--value_max for each column would need to be drastically larger, or the offending table would have to implement several hundred columns.
The URI path which will be used, in conjunction with
--tls_hostname, to create the remote URI for retrieving distributed queries when using the tls distributed plugin.
The URI path which will be used, in conjunction with
--tls_hostname, to create the remote URI for submitting the results of distributed queries when using the tls distributed plugin.
The total number of attempts that will be made to the remote distributed query server if a request fails when using the tls distributed plugin.
Maximum file read size. The daemon or shell will first 'stat' each file before reading. If the reported size is greater than
read_max a "file too large" error will be returned.
Maximum non-super user read size. Similar to
--read_max but applied to user-controlled (owned) files.
osquery daemon runtime control flags
Percent to splay config times. The query schedule often includes several queries with the same interval. It is often not the intention of the schedule author to run these queries together at that interval. But rather, each query should run at about the interval. A default schedule splay of 10% is applied to each query when the configuration is loaded.
Query Packs may optionally include one or more discovery queries, which allow you to use osquery queries to manage which packs should be loaded at runtime. Osquery will natively re-run the discovery queries from time to time, to make sure that all of the correct packs are executing. This flag allows you to specify that interval.
Control the delimiter between pack name and pack query names. When queries are added to the daemon's schedule they inherit the name of the pack. A query named
info within the
general_info pack will become
pack_general_info_info. Changing the delimiter to "/" turned the scheduled name into:
"Caching" refers to short cutting the table implementation and returning the same results from the previous query against the table. This is not related to differential results from scheduled queries, but does affect the performance of the schedule. Results are cached when different scheduled queries in a schedule use the same table, without providing query constraints. Caching should NOT affect data freshness since the cache life is determined as the minimum interval of all queries against a table.
Optionally set the default interval value. This is used if you schedule a query which does not define an interval.
Limit the schedule, 0 for no limit. Optionally limit the
osqueryd's life by adding a schedule limit in seconds. This should only be used for testing.
Comma-delimited list of table names to be disabled. This allows osquery to be launched without certain tables.
osquery events control flags
Disable osquery Operating System eventing publish subscribe APIs. This will implicitly disable several tables that report based on logged events.
Timeout to expire eventing publish subscribe results from the backing-store. This expiration is only applied when results are queried. For example, if
--events_expiry=1 then events will only practically exist for a single select from the subscriber. If no select occurs then events will be saved in the backing store indefinitely.
Since event rows are only "added" it does not make sense to emit "removed" results. An optimization can occur within the osquery daemon's query schedule. Every time the select query runs on a subscriber the current time is saved. Subsequent selects will use the previously saved time as the lower bound. This optimization is removed if any constraints on the "time" column are included.
Maximum number of events to buffer in the backing store while waiting for a query to 'drain' or trigger an expiration. If the expiration (
events_expiry) is set to 1 day, this max value indicates that only 1000 events will be stored before dropping each day. In this case the limiting time is almost always the scheduled query. If a scheduled query that select from events-based tables occurs sooner than the expiration time that interval becomes the limit.
List of Windows event log channels to subscribe to. By default the Windows event log publisher will subscribe to some of the more common major event log channels. However you can subscribe to additional channels using the
Log Name field value in the Windows event viewer. For example, to subscribe to Windows Powershell script block logging one would first enable the feature and then subscribe to the channel with
Logger plugin name. The default logger is filesystem. This writes the various log types as JSON to specific file paths.
Multiple logger plugins may be used simultaneously, effectively copying logs to each interface. Separate plugin names with a comma when specifying the configuration (
Built-in options include: filesystem, tls, syslog, and several Amazon/AWS options.
Disable ERROR/WARNING/INFO (called status logs) and query result logging.
Log scheduled results as events.
Field used to identify the host running osquery: hostname, uuid, ephemeral, instance.
DHCP may assign variable hostnames, if this is the case, you may need a consistent logging label. Three options are available to you:
uuiduses the platform (DMTF) host UUID, fetched at process start.
instanceuses an instance-unique UUID generated at process start, persisted in the backing store.
ephemeraluses an instance-unique UUID generated at process start, not persisted.
Enable verbose informational messages.
Directory path for ERROR/WARN/INFO and results logging.
File mode for output log files (provided as a decimal string). Note that this affects both the query result log and the status logs. Warning: If run as root, log files may contain sensitive information!
Maximum returned row value size.
Set the syslog facility (number) 0-23 for the results log. When using the syslog logger plugin the default facility is 19 at the
LOG_INFO level, which does not log to
@cee: cookie to JSON-formatted messages sent to the syslog logger plugin. Several syslog parsers use this cookie to indicate that the message payload is parseable JSON. The default value is false.
This is default
true and will also send log messages in GLog format to the process's
stderr. The logs are limited by severity and the following flag:
This controls the types of logs sent to the process's
stderr. It does NOT limit or control the types sent to the logger plugin. The default value 2 is
ERROR, set this to
0 for all non-verbose types. If the
--verbose flag is set this value is overridden to
Distributed query service flags
Distributed plugin name. The default distributed plugin is not set. You must set
--disable_distributed=false --distributed_plugin=tls (or whatever plugin you'd rather use instead of TLS) to enable the distributed feature.
Disable distributed queries functionality. By default, this is set to
true (the distributed feature is disabled). Set this to
false to enable distributed queries.
In seconds, the amount of time that osqueryd will wait between periodically checking in with a distributed query server to see if there are any queries to execute.
There is a
syslog virtual table that uses Events and a rsyslog configuration to capture results from syslog. Please see the Syslog Consumption deployment page for more information.
Turn on the syslog ingestion event publisher. This is an 'explicit'-enable because it requires external configuration of rsyslog.
Path to the named pipe used for forwarding rsyslog events.
Maximum number of logs to ingest per run (~200ms between runs). Use this as a fail-safe to prevent osquery from becoming overloaded when syslog is spammed.
Most of the shell flags are self-explanatory and are adapted from the SQLite shell. Refer to the shell's ".help" command for details and explanations.
There are several flags that control the shell's output format:
--csv. For all of the output types there is
--separator that can be used appropriately.
When prototyping new queries the planner enables verbose decisions made by the SQLites virtual table API module. This module is implemented by osquery code so it is very helpful to learn what predicate constraints are selected and what full table scans are required for JOINs and nested queries.
Set this value to
false to disable column name (header) output. If using the shell in an automation or script the header line in
csv mode may not be needed.